Method for the combustion of thin films of liquid fuels, and a burner arrangement for realizing the method

ABSTRACT

Liquid fuel is spread and burned in a thin film on a solid surface, either by pressure of the liquid fuel itself, or else by pressure of a carrier gas. Combustion air is blown parallel along the liquid film. High specific surface of the fuel and high velocity of the fuel and air relative to each other are thus simultaneously achieved.

ilnited States Patent Karoly Somhegyi;

Tamas Rapp; Gyorgy Sasvari, all of Budapest, Hungary Oct. 9, 1969 Aug. 24, 1971 Nikex Nekezipari Kulkereskedelmi Vallalt Budapest, Hungary Oct. 11, 1968 Hungary MA-1895 Inventors Appl. No. Filed Patented Assignee Priority METHOD FOR THE COMBUSTION 0F THIN FILMS OF LlQUlD FUELS, AND A BURNER ARRANGEMENT FOR REALlZING THE METHOD 8 Claims, 2 Drawing Figs.

U.S. Cl

511 lnt.Cl

Primary Examiner Edward G. Favors Att0rney-Young & Thompson ABSTRACT: Liquid fuel is spread and burned in a thin film on a solid surface, either by pressure of the liquid fuel itself, or else by pressure of a carrier gas. Combustion air is blown parallel along the liquid film. High specific surface of the fuel and high velocity of the fuel and air relative to each other are thus simultaneously achieved.

PATENTED AUB24 1971 INVENTORS K/ikoz. y 50/14/956 y/ 714M419 KAPP Gyb'mv SAM/4x1 BY r- JM/ ATTORNEYS METHOD FOR THE COMBUSTION OF THIN FILMS OF LIQUID FUELS, AND A BURNER ARRANGEMENT FOR REALIZING THE METHOD The present invention relates to combustion of thin films of liquid fuels, more particularly to methods and apparatus for the same.

At present, burners for the combustion of liquid fuels are for the most part of one of two principal types: dish burners and atomizing burners. In dish burners, liquid fuel is fed from below and is heated to vaporize the same. The emitted vapors are mixed and burned with air introduced through apertures on the sidewalls of the dish. The air flows essentially perpendicular to the surface of the liquid, and as the quantity and the surface of area of the liquid are necessarily limited, the efficiency is low. Atomizing burners, on the other hand, finely divide the liquid fuel and the droplets are admixed with air.

In general, the efficiency of such burners varies as the specific area of the liquid fuel and the relative velocity between the air and the fuel. The reason for the low efficiency of dish bumers will thus be apparent. But even atomizing burners are of undesirably low efficiency, because a high relative velocity of fuel and air cannot be effected: the droplets of fuel are carried along by the airstream so that there is little relative movement between the air and the droplets. Indeed, the long flames produced by atomizing burners are attributable to this phenomenon: the droplets burn relatively slowly as they are carried along a long path in the air stream.

Accordingly, it is an object of the present invention to provide methods and apparatus for burning liquid fuels in which high relative velocity between the fuel and the air is achieved, while maintaining a desirably high specific surface of the liquid fuel.

Another object of the present invention is the provision of apparatus for the practice of the above method, which will be relatively simple and inexpensive to manufacture, easy to install, operate, maintain and repair, and rugged and durable in use.

Briefly, the present invention provides a combination of high specific surface of the fuel and high relative velocity between the air and the fuel, by spreading the fuel in a thin film on a solid surface by means of fluid pressure, that is, either by the pressure of the liquid fuel itself, or by the pressure of a carrier gas. At the same time, combustion air is blown along the solid surface parallel to the film. The thin film has high specific surface; while the air can be moved at a desired high velocity thereby to effect substantially flameless combustion of the fluid fuel with high efficiency.

Other objects and advantages of the present invention will become apparent from a consideration of the following description, taken in connection with the accompanying drawing, in which:

FIG. 1 is a fragmentary side cross-sectional view of a burner according to the present invention; and

FIG. 2 is a partial cross-sectional view of the burner of FIG. 1, on the plane A ofFIG. 1.

Referring now to the drawing in greater detail, there is shown a burner according to the present invention, by which the method of the present invention may be practiced, comprising a refractory body 1 having a toric surface 2 which is a figure of revolution about the axis 3 of the burner. In FIG. 1, the tangent to a point 4 on surface 2 is shown at 5; and the angle a between tangent 5 and a line 6 parallel to axis 3, increases progressively and regularly in a radially outward direction.

A metallic body 7 is disposed centrally of refractory body 1 and comprises the inlet and outlet ducts for liquid fuel and air, and also a carrier gas if a carrier gas is used. Thus, a liquid fuel, which is oil in the illustrated embodiment, enters at 8 through a screw-threaded connector 9 and flows into an annular distributing chamber 10. From chamber 10, the oil flows through a plurality of ducts 11 to circular channel 12 and thence out through a circular outlet slot 13.

A carrier gas, such as air. under pressure enters at 14 and flows through a screw-threaded fitting 15 to a circular chamber 16, and then through parallel channels 17 to a circular channel 18. Finally, combustion air enters at 19 and passes through a threaded fitting 20. Parallel channels 21 are defined by a centrally disposed spider which has a mushroom-shaped head or deflector 22 that defines on its underside a chamber 23 that is progressively more restricted in the direction of airflow and that curves outwardly and then downwardly as seen in FIG. 1 and terminates in an annular outlet slot 24.

In operation, liquid fuel emerges from the slot 13 and is blown in a thin film radially outwardly across surface 2 by means of the carrier gas emerging from channel 18. If no carrier gas is used, then reliance is had on the pressure of the liquid fuel, to throw the liquid fuel out in' a thin film across surface 2. The combustion air emerging from slot 24 then moves over the thin film with any desired relative velocity.

Ignition means (not shown) may also be provided for igniting the resulting mixture of fuel vapors and air. Also, the burner may be set in the wall of a combustion chamber.

It should be noted that the liquid fuel is introduced on the surface of the solid body at its own fluid pressure or, if in a carrier gas, at the pressure of the carrier gas. It will also be noted from the drawing that the burner has three inlet ducts but only two apertures or slots through which the gases or fluid arrive at the concave surface of the refractory solid body. One of the inlets is for liquid fuel, another for carrier gases, and a third for combustion air. The liquid fuel and carrier gas, however, have a common outlet, and this is arranged quite close to the surface of the refractory body; whereas the aperture for admitting the combustion air is disposed somewhat farther away from the surface of the refractory body. In any event, the direction of the streams of fuel and gas is tangential to the refractory surface at the point of impingement thereon.

Finally, it will be noted that the combustion air is emitted from points closely adjacent and in the same direction as the liquid fuel.

From a consideration of the foregoing disclosure, therefore, it will be evident that all the initially recited objects of the present invention have been achieved.

Although the present invention has been described and illustrated in connection with a preferred embodiment, it is to be understood that modifications and variations may be resorted to without departing fromthe spirit of the invention, as those skilled in this art will readily understand. For example, the surface 2 may be so formed that the liquid fuel inlet is at the deepest part of the curve. This and other modifications and variations are considered to be within the purview and scope of the present invention as defined by the appended claims.

Having described our invention, we claim:

1. A method of burning liquid fuel, comprising forming a film of liquid fuel on a solid surface, blowing combustion air along and parallel to said surface to form a mixture of combustion air and fuel vapors, the liquid fuel and the combustion air emanating from points close to each other and being directed in the same direction along said surface, projecting said liquid fuel and a carrier gas for said liquid fuel from a common outlet therefor which is separate from the outlet for said combustion air, and combusting said mixture.

2. A method as claimed in claim 1 and directing said fuel and combustion air radially outwardly from the center of and along a surface which is figure of revolution about said center.

3. A burner for the combustion of liquid fuels in a gas stream, the burner having a solid surface, means for separately introducing into said burner a liquid fuel, a carrier gas for spreading said liquid fuel in a thin film on said surface, and combustion air, said burner having a common outlet for said carrier gas and said liquid fuel for directing said liquid fuel along said surface in a thin film, said burner having a separate outlet for said combustion air for directing said combustion air along the surface of saidthin film.

4. A burner as claimed in claim 3, in which said surface is concave.

5. Apparatus as claimed in claim 4, said concave surface 7. Apparatusas claimed in claim 6, said outlet for said liquid being a figure of revolution about an axis, said directing means fuel being disposed more closely adjacent said surface than comprising means for directing said liquid fuel and said com- Said Outlet for combustion bustion air radially outwardly in all directions about said axis. A burner as claimed in Claim 6, Said Outlets being in the A bummas claimed in claim 3 Said surface being Com form of annular slots that direct streams of fluid radially outcave and said outlets being directed tangentially for said surwardly in all directions along Said Surfaceface. 

2. A method as claimed in claim 1 and directing said fuel and combustion air radially outwardly from the center of and along a surface which is figure of revolution about said center.
 3. A burner for the combustion of liquid fuels in a gas stream, the burner having a solid surface, means for separately introducing into said burner a liquid fuel, a carrier gas for spreading said liquid fuel in a thin film on said surface, and combustion air, said burner having a common outlet for said carrier gas and said liquid fuel for directing said liquid fuel along said surface in a thin film, said burner having a separate outlet for said combustion air for directing said combustion air along the surface of said thin film.
 4. A burner as claimed in claim 3, in which said surface is concave.
 5. Apparatus as claimed in claim 4, said concave surface being a figure of revolution about an axis, said directing means comprising means for directing said liquid fuel and said combustion air radially outwardly in all directions about said axis.
 6. A burner as claimed in claim 3, said surface being concave and said outlets being directed tangentially for said surface.
 7. Apparatus as claimed in claim 6, said outlet for said liquid fuel being disposed more closely adjacent said surface than said outlet for combustion air.
 8. A burner as claimed in claim 6, said outlets being in the form of annular slots that direct streams of fluid radially outwardly in all directions along said surface. 